Balancing the current distribution in the current collectors of homopolar machines using induced voltage gradients

This paper presents the results of a study conducted at the Westinghouse Electric Corporation Research Center for minimizing the current imbalance in sliding contact current collector assemblies. The results suggest that the conventional approach to achieving current balance in these assemblies provides a less than optimal distribution and that significant improvements can be made. The optimum situation for minimizing current imbalance is not necessarily one where a constant potential is maintained along the current collector, but one where a voltage gradient is induced from inboard to outboard end of the collector. Described is a calculation procedure for determining the optimum voltage profile within the collector as well as the leakage field needed to induce this required voltage gradient.